1. Field of the Invention
The present invention relates to an explosive actuated acoustic device, and in particular, to an acoustic device used underwater.
2. Description of the Prior Art
Acoustic devices for use underwater, such as acoustic devices for preventing detection of ships by acoustic torpedoes or other sound sensitive devices are well known. The devices are deployed as a torpedo countermeasure to prevent a homing system from finding a ship. It is desired that such devices are easily deployed to cover an extended area at a number of depths rather than emitting sound from a point source, in order to provide better protection for the ships. In addition to extended area, it is also desired that acoustic systems have sound emitted over a period of time for additional protection.
Previous acoustic devices have been electrically actuated, thereby requiring an electric power supply. In addition, the previous devices have emitted sound from a point source suspended in the water, giving very little coverage for masking purposes. Since the devices are suspended in water, flotation devices are required as part of the design, adding to complexity and cost. Types of flotation devices used include cables, flotation bottles, flotation bags, and hover motors equipped with propellers to provide positive and negative thrust, all of which may be unreliable at providing proper depth for the acoustic devices. When such devices are launched from a vessel, a parachute is required to ensure that the impact with the water does not cause the devices to malfunction or actuate prematurely. Another problem is that the sound generated by electronic means may not be sufficient for covering the sound of ships. Since the acoustic devices are electric, the reliability decreases in the wet conditions in which the devices are deployed.
Acoustic devices must also be safe to use. The devices may be accidentally actuated prematurely. Movement of the launch vehicle may jar the devices if safety features are not incorporated, causing the acoustic device to explode prematurely. This may start a chain reaction wherein all acoustic devices in the vehicles are detonated.
The acoustic devices could also be actuated upon impact with the water. An explosive-actuated acoustic device should incorporate safeguards to prevent premature actuation from impact with the water.
It can be seen then, that an improved system for acoustic torpedo countermeasures is needed. An improved system should cover a sufficient area, for an extended period, at a satisfactory sound level. In addition, such an acoustic system should be compact, easily deployable, and reliable under various conditions. Such a system should also incorporate safety features to prevent premature actuation.